dns: make the dns name resolver a plugin

Type: refactor
Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I823c2cd307a4613653a2d20f564dda062d4da31b

1 files changed, 344 insertions, 0 deletions

diff --git a/src/plugins/dns/request_node.c b/src/plugins/dns/request_node.c
new file mode 100644
index 00000000000..d26e579cf47
--- /dev/null
+++ b/src/plugins/dns/request_node.c
@@ -0,0 +1,344 @@
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <dns/dns.h>
+
+#include <vlib/vlib.h>
+#include <vnet/vnet.h>
+
+vlib_node_registration_t dns46_request_node;
+
+typedef struct
+{
+  u32 pool_index;
+  u32 disposition;
+} dns46_request_trace_t;
+
+/* packet trace format function */
+static u8 *
+format_dns46_request_trace (u8 * s, va_list * args)
+{
+  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
+  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
+  dns46_request_trace_t *t = va_arg (*args, dns46_request_trace_t *);
+
+  s = format (s, "DNS46_REPLY: pool index %d, disposition  %d",
+	      t->pool_index, t->disposition);
+  return s;
+}
+
+vlib_node_registration_t dns46_request_node;
+
+static char *dns46_request_error_strings[] = {
+#define _(sym,string) string,
+  foreach_dns46_request_error
+#undef _
+};
+
+typedef enum
+{
+  DNS46_REQUEST_NEXT_DROP,
+  DNS46_REQUEST_NEXT_IP_LOOKUP,
+  DNS46_REQUEST_NEXT_PUNT,
+  DNS46_REQUEST_N_NEXT,
+} dns46_request_next_t;
+
+static uword
+dns46_request_inline (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame,
+		      int is_ip6)
+{
+  u32 n_left_from, *from, *to_next;
+  dns46_request_next_t next_index;
+  dns_main_t *dm = &dns_main;
+
+  from = vlib_frame_vector_args (frame);
+  n_left_from = frame->n_vectors;
+  next_index = node->cached_next_index;
+
+  while (n_left_from > 0)
+    {
+      u32 n_left_to_next;
+
+      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
+#if 0
+      while (n_left_from >= 4 && n_left_to_next >= 2)
+	{
+	  u32 next0 = DNS46_REQUEST_NEXT_INTERFACE_OUTPUT;
+	  u32 next1 = DNS46_REQUEST_NEXT_INTERFACE_OUTPUT;
+	  u32 sw_if_index0, sw_if_index1;
+	  u8 tmp0[6], tmp1[6];
+	  ethernet_header_t *en0, *en1;
+	  u32 bi0, bi1;
+	  vlib_buffer_t *b0, *b1;
+
+	  /* Prefetch next iteration. */
+	  {
+	    vlib_buffer_t *p2, *p3;
+
+	    p2 = vlib_get_buffer (vm, from[2]);
+	    p3 = vlib_get_buffer (vm, from[3]);
+
+	    vlib_prefetch_buffer_header (p2, LOAD);
+	    vlib_prefetch_buffer_header (p3, LOAD);
+
+	    CLIB_PREFETCH (p2->data, CLIB_CACHE_LINE_BYTES, STORE);
+	    CLIB_PREFETCH (p3->data, CLIB_CACHE_LINE_BYTES, STORE);
+	  }
+
+	  /* speculatively enqueue b0 and b1 to the current next frame */
+	  to_next[0] = bi0 = from[0];
+	  to_next[1] = bi1 = from[1];
+	  from += 2;
+	  to_next += 2;
+	  n_left_from -= 2;
+	  n_left_to_next -= 2;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  b1 = vlib_get_buffer (vm, bi1);
+
+	  /* $$$$$ End of processing 2 x packets $$$$$ */
+
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)))
+	    {
+	      if (b0->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  dns46_request_trace_t *t =
+		    vlib_add_trace (vm, node, b0, sizeof (*t));
+		  t->sw_if_index = sw_if_index0;
+		  t->next_index = next0;
+		}
+	      if (b1->flags & VLIB_BUFFER_IS_TRACED)
+		{
+		  dns46_request_trace_t *t =
+		    vlib_add_trace (vm, node, b1, sizeof (*t));
+		  t->sw_if_index = sw_if_index1;
+		  t->next_index = next1;
+		}
+	    }
+
+	  /* verify speculative enqueues, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, bi1, next0, next1);
+	}
+#endif
+
+      while (n_left_from > 0 && n_left_to_next > 0)
+	{
+	  u32 bi0;
+	  vlib_buffer_t *b0;
+	  u32 next0 = DNS46_REQUEST_NEXT_DROP;
+	  u32 error0 = DNS46_REQUEST_ERROR_NONE;
+	  udp_header_t *u0;
+	  dns_header_t *d0;
+	  dns_query_t *q0;
+	  ip4_header_t *ip40 = 0;
+	  ip6_header_t *ip60 = 0;
+	  dns_cache_entry_t *ep0;
+	  dns_pending_request_t _t0, *t0 = &_t0;
+	  u16 flags0;
+	  u32 pool_index0 = ~0;
+	  u8 *name0;
+	  u8 *label0;
+
+	  /* speculatively enqueue b0 to the current next frame */
+	  bi0 = from[0];
+	  to_next[0] = bi0;
+	  from += 1;
+	  to_next += 1;
+	  n_left_from -= 1;
+	  n_left_to_next -= 1;
+
+	  b0 = vlib_get_buffer (vm, bi0);
+	  d0 = vlib_buffer_get_current (b0);
+	  u0 = (udp_header_t *) ((u8 *) d0 - sizeof (*u0));
+
+	  if (PREDICT_FALSE (dm->is_enabled == 0))
+	    {
+	      next0 = DNS46_REQUEST_NEXT_PUNT;
+	      goto done0;
+	    }
+
+	  if (is_ip6)
+	    {
+	      ip60 = (ip6_header_t *) (((u8 *) u0) - sizeof (ip6_header_t));
+	      next0 = DNS46_REQUEST_NEXT_DROP;
+	      error0 = DNS46_REQUEST_ERROR_UNIMPLEMENTED;
+	      goto done0;
+	    }
+	  else
+	    {
+	      ip40 = (ip4_header_t *) (((u8 *) u0) - sizeof (ip4_header_t));
+	      if (ip40->ip_version_and_header_length != 0x45)
+		{
+		  error0 = DNS46_REQUEST_ERROR_IP_OPTIONS;
+		  goto done0;
+		}
+	    }
+	  /* Parse through the DNS request */
+	  flags0 = clib_net_to_host_u16 (d0->flags);
+
+	  /* Requests only */
+	  if (flags0 & DNS_QR)
+	    {
+	      next0 = DNS46_REQUEST_NEXT_DROP;
+	      error0 = DNS46_REQUEST_ERROR_BAD_REQUEST;
+	      goto done0;
+	    }
+	  if (clib_net_to_host_u16 (d0->qdcount) != 1)
+	    {
+	      next0 = DNS46_REQUEST_NEXT_DROP;
+	      error0 = DNS46_REQUEST_ERROR_TOO_MANY_REQUESTS;
+	      goto done0;
+	    }
+
+	  label0 = (u8 *) (d0 + 1);
+
+	  /*
+	   * vnet_dns_labels_to_name produces a non NULL terminated vector
+	   * vnet_dns_resolve_name expects a C-string.
+	   */
+	  name0 = vnet_dns_labels_to_name (label0, (u8 *) d0, (u8 **) & q0);
+	  vec_add1 (name0, 0);
+	  _vec_len (name0) -= 1;
+
+	  t0->request_type = DNS_PEER_PENDING_NAME_TO_IP;
+
+	  /*
+	   * See if this is a reverse lookup. Both ip4 and ip6 reverse
+	   * requests end with ".arpa"
+	   */
+	  if (PREDICT_TRUE (vec_len (name0) > 5))
+	    {
+	      u8 *aptr0 = name0 + vec_len (name0) - 5;
+
+	      if (!memcmp (aptr0, ".arpa", 5))
+		t0->request_type = DNS_PEER_PENDING_IP_TO_NAME;
+	    }
+
+	  t0->client_index = ~0;
+	  t0->is_ip6 = is_ip6;
+	  t0->dst_port = u0->src_port;
+	  t0->id = d0->id;
+	  t0->name = name0;
+	  if (is_ip6)
+	    clib_memcpy_fast (t0->dst_address, ip60->src_address.as_u8,
+			      sizeof (ip6_address_t));
+	  else
+	    clib_memcpy_fast (t0->dst_address, ip40->src_address.as_u8,
+			      sizeof (ip4_address_t));
+
+	  vnet_dns_resolve_name (dm, name0, t0, &ep0);
+
+	  if (ep0)
+	    {
+	      if (is_ip6)
+		vnet_send_dns6_reply (dm, t0, ep0, b0);
+	      else
+		vnet_send_dns4_reply (dm, t0, ep0, b0);
+	      next0 = DNS46_REQUEST_NEXT_IP_LOOKUP;
+	    }
+	  else
+	    {
+	      error0 = DNS46_REQUEST_ERROR_RESOLUTION_REQUIRED;
+	    }
+
+	done0:
+	  b0->error = node->errors[error0];
+
+	  if (PREDICT_FALSE ((node->flags & VLIB_NODE_FLAG_TRACE)
+			     && (b0->flags & VLIB_BUFFER_IS_TRACED)))
+	    {
+	      dns46_request_trace_t *t =
+		vlib_add_trace (vm, node, b0, sizeof (*t));
+	      t->disposition = error0;
+	      t->pool_index = pool_index0;
+	    }
+
+	  /* verify speculative enqueue, maybe switch current next frame */
+	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
+					   to_next, n_left_to_next,
+					   bi0, next0);
+	}
+
+      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
+    }
+
+  return frame->n_vectors;
+}
+
+static uword
+dns4_request_node_fn (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+
+  return dns46_request_inline (vm, node, frame, 0 /* is_ip6 */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dns4_request_node) =
+{
+  .function = dns4_request_node_fn,
+  .name = "dns4-request",
+  .vector_size = sizeof (u32),
+  .format_trace = format_dns46_request_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (dns46_request_error_strings),
+  .error_strings = dns46_request_error_strings,
+  .n_next_nodes = DNS46_REQUEST_N_NEXT,
+  .next_nodes = {
+    [DNS46_REQUEST_NEXT_DROP] = "error-drop",
+    [DNS46_REQUEST_NEXT_PUNT] = "error-punt",
+    [DNS46_REQUEST_NEXT_IP_LOOKUP] = "ip4-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+static uword
+dns6_request_node_fn (vlib_main_t * vm,
+		      vlib_node_runtime_t * node, vlib_frame_t * frame)
+{
+
+  return dns46_request_inline (vm, node, frame, 1 /* is_ip6 */ );
+}
+
+/* *INDENT-OFF* */
+VLIB_REGISTER_NODE (dns6_request_node) =
+{
+  .function = dns6_request_node_fn,
+  .name = "dns6-request",
+  .vector_size = sizeof (u32),
+  .format_trace = format_dns46_request_trace,
+  .type = VLIB_NODE_TYPE_INTERNAL,
+  .n_errors = ARRAY_LEN (dns46_request_error_strings),
+  .error_strings = dns46_request_error_strings,
+  .n_next_nodes = DNS46_REQUEST_N_NEXT,
+  .next_nodes = {
+    [DNS46_REQUEST_NEXT_DROP] = "error-drop",
+    [DNS46_REQUEST_NEXT_PUNT] = "error-punt",
+    [DNS46_REQUEST_NEXT_IP_LOOKUP] = "ip6-lookup",
+  },
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */